Virginia's Declaration of Rights was drawn upon by Thomas Jefferson for the opening paragraphs of the Declaration of Independence. It was widely copied by the other colonies and became the basis of the Bill of Rights.
The ridges found in flexible metal duct create turbulence and will diminish airflow. NEVER use 4 dryer duct or any plastic duct on a range hood installation. The minimum size duct allowed on most range hoods is 3 Â¼ by 10 which is equivalent to 6 round. More powerful hoods require even larger duct sizes up to 10 round. Consult the specifications for the model you have chosen.
If so, then you need a very, very good range hood with serious cfms and sizing. The ideal location for a range or cooktop is against a wall where the wall and surrounding cabinets help in the capture of the grease, smoke, steam, fumes, odors, etc. Ideally, a hood would be at least 24 deep and 6 wider than the cooking surface (so a 30 range or cooktop would have a 36 hood).